Shell shock is a term coined in World War I by British psychologist Charles Samuel Myers to describe the type of post traumatic stress disorder many soldiers were afflicted with during the war (before PTSD was termed). ... During the War, the concept of shell shock was ill-defined.
A cliche is a worn out expression. I hope this helped :D
Very sure the answer is D
The Balkans were known as "the powder keg of Europe" because they were ready to "explode" at any moment, with tensions from multiple countries in the region.
